Abstract
AbstractAn in‐depth investigation of the network topology for a series of sodium acrylate hydrogels synthesized via conventional free radical polymerization (FRP) and reversible addition–fragmentation chain transfer (RAFT) polymerization is conducted. The role of the RAFT agent on the crosslinking process is demonstrated on a model system upon analysis of the reaction mixture via size‐exclusion chromatography before the gelation point. For a comprehensive study, both the impact of the amount of RAFT agent and of the degree of crosslinking on the microstructure of the final product are systematically investigated. In addition to swelling experiments and oscillatory shear rheology measurements, the resulting networks are analyzed via low‐field proton nuclear magnetic resonance (1H‐NMR) techniques such as transverse relaxation and double‐quantum coherence to evaluate the network mobility, which is then correlated to structural inhomogeneity. A broader mobility distribution is observed for the RAFT mediated networks compared to the FRP samples, which can be assigned to a higher content of dangling ends in the former case. The results are further elaborated to propose a mechanism for network formation in presence of a RAFT agent.
Highlights
An in-depth investigation of the network topology for a series of sodium acrylate swells rather than dissolve.[4]
Methyl acrylate (MA), which is the ester of the acrylic acid (AA), was chosen as a monomer to suppress enthalpic interaction of the analyte with the stationary phase in the aqueous Size-exclusion chromatography (SEC), which can occur in case of AA samples
The impact of two different synthetic procedures, that is, reversible addition–fragmentation chain transfer (RAFT) polymerization and conventional free radical polymerization (FRP), on the topology of the resulting networks was compared for poly(sodium acrylate) based hydrogels
Summary
An in-depth investigation of the network topology for a series of sodium acrylate swells rather than dissolve.[4]. Both the of the gel for the solvent, which in turn is determined by the chemistry of the polymer backbone.[5] For example, hydrogels are networks able to swell in water due to the presence of hydrophilic groups impact of the amount of RAFT agent and of the degree of crosslinking on the on the polymer chain.[6] The water absormicrostructure of the final product are systematically investigated. Cally or covalently crosslinked with each other.[1,2,3] The par- or to recover energy in an osmotic engine[18] was recently proticular microstructure of polymer networks makes the material posed. The network microstructure plays an important role for the achievement of, for
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